This invention relates, inter alia, to novel compositions of matter useful, inter alia, as cocatalysts, to novel catalyst compositions made using such cocatalysts, to methods for preparing these catalysts, and to methods for polymerization utilizing such catalysts.
The use of soluble Ziegler-Natta type catalysts in the polymerization of olefins is well known in the prior art. In general, such systems include a Group 4 metal compound and a metal or metalloid alkyl cocatalyst, such as aluminum alkyl cocatalyst. More broadly, it may be said to include a mixture of a Group 1, 2 or 13 metal alkyl and a transition metal complex from Group 4-5 metals, particularly titanium, zirconium, or hafnium with aluminum alkyl cocatalysts.
First generation cocatalyst systems for homogeneous metallocene Ziegler-Natta olefin polymerization, alkylaluminum chlorides (AlR2Cl), exhibit low ethylene polymerization activity levels and no propylene polymerization activity. Second generation cocatalyst systems, utilizing methyl aluminoxane (MAO), raise activities by several orders of magnitude. In practice however, a large stoichiometric excess of MAO over catalyst ranging from several hundred to ten thousand must be employed to have good activities and stereoselectivities. Moreover, it has not been possible to isolate characterizable metallocene active species using MAO. The third generation of cocatalyst, B(C6F5)3, proves to be far more efficient while utilizing a 1:1 catalyst-cocatalyst ratio. Although active catalyst species generated with B(C6F5)3, are isolable and characterizable, the anion MeB(C6F5)3xe2x8ax96, formed after Mexe2x8ax96 abstraction from metallocene dimethyl complexes, is weakly coordinated to the electron-deficient metal center, thus resulting in a drop of certain catalytic activities. The recently developed B(C6F5)4xe2x8ax96 type of non-coordinating anion exhibits some of the highest reported catalytic activities, but such catalysts have proven difficult to obtain in the pure state due to poor thermal stability and poor crystallizability, which is crucial for long-lived catalysts and for understanding the role of true catalytic species in the catalysis for the future catalyst design. Synthetically, it also takes two more steps to prepare such an anion than for the neutral organo-Lewis acid.
In our prior applications referred to hereinabove, and in publications appearing in J. Am. Chem. Soc. 1997, 119, 2582-2583, and J. Am. Chem. Soc. 1998, 120, 6287-6305 new, sterically encumbered (polyfluoroaryl)fluoroanions of aluminum, such as tris(perfluorobiphenyl)fluoroaluminate (PBA)xe2x8ax96, and the preparation and use of such anions as highly efficient cocatalysts for metallocene-mediated olefin polymerization are described. The catalytically active species generated from Ph3C⊕PBAxe2x8ax96 are isolable and X-ray crystallographically characterizable instead of the unstable, oily residues which often result in the case of B(C6F5)4xe2x8ax96.
This invention provides, inter alia, technology described in the above-referred-to prior applications, and additionally, improvements in the technology described in the above-referred-to prior applications.
Accordingly, it is an object of the subject invention to provide, prepare and utilize new types of weakly coordinating anions which form organo-Lewis acid salts that are useful in forming novel, highly-effective olefin polymerization catalysts.
A further object of the subject invention is to provide a catalyst which permits better control over molecular weight, molecular distribution, stereoselectivity, and/or comonomer incorporation.
Another object of the subject invention is to provide a Ziegler-Natta type catalyst system which reduces the use of excess cocatalyst and activates previously unresponsive metallocenes.
In accordance with one of its embodiments, this invention provides novel (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium which may be represented by the formula
[ERxe2x80x2Rxe2x80x3Rxe2x80x2xe2x80x3F]xe2x8ax96xe2x80x83xe2x80x83(I)
wherein E is aluminum, gallium, or indium, wherein F is fluorine, wherein Rxe2x80x2 is a fluoroaryl group having at least one additional substituent other than fluorine, wherein Rxe2x80x3 and Rxe2x80x2xe2x80x3 each is, independently, (i) a fluoroaryl group having at least one additional substituent other than fluorine, or (ii) a fluorinated aryl group devoid of additional substitution. Preferably, E is aluminum. In these compounds, Rxe2x80x3 and Rxe2x80x2xe2x80x3 are preferably the same as each other and, preferably, are fluoroaryl groups having at least one additional substituent other than fluorine. Most preferably, Rxe2x80x2 of formula (I) is the same as Rxe2x80x3 and Rxe2x80x2xe2x80x3. The substituent(s) other than fluorine present in the (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium of formula (I) can be (i) one or more substituents which increase the solubility of the compound in an organic solvent as compared to the corresponding compound in which each such substituent other than fluorine is replaced by a fluorine atom, (ii) one or more electron withdrawing substituents other than fluorine, or (iii) a combination of at least one substituent from (i) and at least one substituent from (ii).
A second embodiment provides (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium which may be referred to by the formula
[ERxe2x80x2Rxe2x80x3Rxe2x80x2xe2x80x3F]xe2x8ax96xe2x80x83xe2x80x83(II)
wherein E is aluminum, gallium, or indium, wherein F is fluorine, where at least one of Rxe2x80x2, Rxe2x80x3, and Rxe2x80x2xe2x80x3 is a fluorinated biphenyl or fluorinated polycyclic fused ring group such as naphthyl, anthracenyl or fluorenyl. E is preferably aluminum. Preferably two, and more preferably all three, of Rxe2x80x2, Rxe2x80x3, and Rxe2x80x2xe2x80x3 are fluorinated biphenyl or fluorinated polycyclic fused ring groups such as naphthyl, anthracenyl or fluorenyl. Two of the biphenyl groups may be replaced by a phenyl group. That is, Rxe2x80x2 is a biphenyl group and Rxe2x80x3 and Rxe2x80x2xe2x80x3 each is a phenyl group. The biphenyl groups and the phenyl groups plus any polycyclic fused ring group or groups of the compounds of formula (II) should be highly fluorinated, preferably with only one or two hydrogen atoms on a group, and most preferably, as in PBAxe2x8ax96, with no hydrogen atoms and all fluorine substituents. Thus in one subgroup of these (polyfluoroaryl)fluoroanions, Rxe2x80x2 of formula (II) is a fluorobiphenyl group having 0 to 2 hydrogen atoms and 7 to 9 fluorine atoms on the rings thereof, the sum of the foregoing integers being 9, and Rxe2x80x3 and Rxe2x80x2xe2x80x3 of formula (II) each is a phenyl group having 0 to 2 hydrogen atoms and 3 to 5 fluorine atoms on the ring, the sum of the foregoing integers being 5. In this subgroup, most preferably Rxe2x80x2 is nonafluorobiphenyl and Rxe2x80x3 and Rxe2x80x2xe2x80x3 each is a pentafluorophenyl group, i.e., the compound is nonafluorobiphenylbis(pentafluorophenyl)fluoroaluminate. In another subgroup of these (polyfluoroaryl)fluoroanions, Rxe2x80x2 of formula (II) is a fluorobiphenyl group having 0 to 2 hydrogen atoms and 7 to 9 fluorine atoms on the rings thereof, the sum of the foregoing integers being 9, and Rxe2x80x3 and Rxe2x80x2xe2x80x3 of formula (II) each is a fluorinated polycyclic fused ring group such as naphthyl, anthracenyl or fluorenyl. Preferably the polycyclic fused ring group is perfluorinated. However, the fused rings may have one or two hydrogen atoms on the ring with the other available positions occupied by fluorine. A third subgroup of (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium of this second embodiment are tris(fluorobiphenyl)fluoroaluminates wherein Rxe2x80x2 of formula (II) and Rxe2x80x3 and Rxe2x80x2xe2x80x3 of formula (II) each is a fluorobiphenyl group having 0 to 2 hydrogen atoms and 7 to 9 fluorine atoms on the rings thereof, the sum of the foregoing integers being 9, especially where such fluorobiphenyl groups are all the same as each other. The most preferred compound of this third sub-group is tris(perfluorobiphenyl)fluoroaluminate.
A third embodiment of this invention is comprised of (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium of the formula:
[E(R1)n(R2)3xe2x88x92nF]xe2x8ax96xe2x80x83xe2x80x83(III)
wherein E is aluminum, gallium, or indium, wherein F is fluorine, wherein each R1 is, independently, a perfluorinated polycyclic fused ring group in which the ring system is totally aromatic (e.g., as in naphthyl or anthracenyl), or is partially aromatic and partially cycloaliphatic, (e.g., as in tetrahydronaphthyl, acenaphthyl, indenyl, or fluorenyl), wherein each R2 is a pentafluorophenyl group, and wherein n is 1 to 3. Such anions include, for example:
tris(nonafluoroanthracenyl)fluoroaluminate,
bis(nonafluoroanthracenyl)(pentafluorophenyl)fluoroaluminate,
nonafluoroanthracenylbis(pentafluorophenyl)fluoroaluminate,
tris(undecafluorotetrahydronaphthyl)fluoroaluminate,
bis(undecafluorotetrahydronaphthyl)(pentafluorophenyl)fluoroaluminate,
undecafluorotetrahydronaphthylbis(pentafluorophenyl)fluoroaluminate,
tris(nonafluorofluorenyl)fluoroaluminate,
bis(nonafluorofluorenyl)(pentafluorophenyl)fluoroaluminate, and
nonafluorofluorenylbis(pentafluorophenyl)fluoroaluminate.
Anions of this embodiment in which less than half of the fluorine atoms, and preferably up to about 3 fluorine atoms, are replaced by a corresponding number of substituents other than fluorine are included within the scope of the first embodiment described above.
It will thus be seen that this invention provides various new metallic compounds in which an anion of formulas (I), (II), or (III) is paired with a suitable cation, such as an alkali metal cation, or a carbonium cation.
A fourth embodiment of this invention provides a novel complex or ion pair formed from a (polyfluoroaryl)fluoroanion of aluminum, gallium, or indium of the first embodiment. In particular, the novel complex or ion pair of this fourth embodiment comprises a cation formed from a d-block or f-block metal compound by abstraction therefrom of a leaving group (e.g., a methyl group), and formation of an ion pair comprised of a cation formed from the d-block or f-block metal compound and a (polyfluoroaryl)fluoroanion of aluminum, gallium, or indium of the formula [ERxe2x80x2Rxe2x80x3Rxe2x80x2xe2x80x3F]xe2x8ax96. In this formula, E is aluminum, gallium, or indium, F is fluorine, Rxe2x80x2 is a fluoroaryl group having at least one additional substituent other than fluorine, and Rxe2x80x3 and Rxe2x80x2xe2x80x3 each is, independently, (i) a fluoroaryl group having at least one additional substituent other than fluorine, or (ii) a fluorinated hydrocarbyl group devoid of additional substitution.
A fifth embodiment of this invention provides a novel complex or ion pair formed from a (polyfluoroaryl)fluoroanion of aluminum, gallium, or indium of the third embodiment. Thus in accordance with this fifth embodiment, the complex or ion pair comprises a cation formed from a d-block or f-block metal compound by abstraction therefrom of a leaving group (e.g., a methyl group), and formation of an ion pair comprised of a cation formed from the d-block or f-block metal compound and a (polyfluoroaryl)fluoroanion of aluminum, gallium, or indium of the formula [E(R1)n(R2)3xe2x88x92nF]xe2x8ax96. In this formula, E is aluminum, gallium, or indium, F is fluorine, each R1 is, independently, a perfluorinated polycyclic fused ring group in which the ring system is totally aromatic (e.g., as in naphthyl or anthracenyl), or is partially aromatic and partially cycloaliphatic, (e.g., as in tetrahydronaphthyl, acenaphthyl, indenyl, or fluorenyl), each R2 is a pentafluorophenyl group, and n is 1 to 3.
In a sixth embodiment of this invention, a novel catalytic complex or ion pair is produced by a process which comprises contacting a d-block or f-block metal compound having at least one leaving group (e.g., a methyl group) with an organocation salt of a (polyfluoroaryl)fluoroanion of aluminum, gallium, or indium of the formula [ERxe2x80x2Rxe2x80x3Rxe2x80x2xe2x80x3F]xe2x8ax96. In this formula, E is aluminum, gallium, or indium, F is fluorine, Rxe2x80x2 is a fluoroaryl group having at least one additional substituent other than fluorine, and Rxe2x80x3 and Rxe2x80x2xe2x80x3 each is, independently, (i) a fluoroaryl group having at least one additional substituent other than fluorine, or (ii) a fluorinated hydrocarbyl group devoid of additional substitution. In this process, which typically is conducted in a suitable anhydrous liquid solvent and in a suitably inert atmosphere or environment, a leaving group is abstracted from the d-block or f-block metal compound by the organocation, and an ion pair comprised of a cation formed from the d-block or f-block metal compound and the (polyfluoroaryl)fluoroanion of aluminum, gallium, or indium is formed to produce the catalytic complex.
A seventh embodiment is analogous to the process of the sixth embodiment except that the (polyfluoroaryl)fluoroanion of aluminum, gallium, or indium has the formula [E(R1)n(R2)3xe2x88x92nF]xe2x8ax96 wherein E is aluminum, gallium, or indium, wherein F is fluorine, wherein each Rxe2x80x2 is, independently, a perfluorinated polycyclic fused ring group in which the ring system is totally aromatic (e.g., as in naphthyl or anthracenyl), or is partially aromatic and partially cycloaliphatic, (e.g., as in tetrahydronaphthyl, acenaphthyl, indenyl, or fluorenyl), wherein each R2 is a pentafluorophenyl group, and wherein n is 1 to 3.
An eighth embodiment of this invention is a process for polymerizing an olefinic monomer or copolymerizing two or more olefinic monomers, which process comprises contacting the monomer or monomers, preferably a single vinyl monomer or two or more copolymerizable vinyl monomers, with a polymerization catalyst complex which comprises a cation formed from a d-block or f-block metal compound by abstraction therefrom of a leaving group (e.g., a methyl group), and formation of an ion pair comprised of a cation formed from the d-block or f-block metal compound and a (polyfluoroaryl)fluoroanion of aluminum, gallium, orindium of the formula [ERxe2x80x2Rxe2x80x3Rxe2x80x2xe2x80x3F]xe2x8ax96 wherein E is aluminum, gallium, or indium, wherein F is fluorine, wherein Rxe2x80x2 is a fluoroaryl group having at least one additional substituent other than fluorine, and wherein Rxe2x80x3 and Rxe2x80x2xe2x80x3 each is, independently, (i) a fluoroaryl group having at least one additional substituent other than fluorine, or (ii) a fluorinated hydrocarbyl group devoid of additional substitution.
A ninth embodiment is analogous to the polymerization process of the eighth embodiment except that the (polyfluoroaryl)fluoroanion of aluminum, gallium, or indium has the formula [E(R1)n(R2)3xe2x88x92nF]xe2x8ax96 wherein E is aluminum, gallium, or indium, wherein F is fluorine, wherein each R1 is, independently, a perfluorinated polycyclic fused ring group in which the ring system is totally aromatic (e.g., as in naphthyl or anthracenyl), or is partially aromatic and partially cycloaliphatic, (e.g., as in tetrahydronaphthyl, acenaphthyl, indenyl, or fluorenyl), wherein each R2 is a pentafluorophenyl group, and wherein n is 1 to 3.
These and other objects, embodiments, features and advantages of this invention will be apparent from the ensuing description, appended claims, and accompanying Drawings.